The invention relates to an apparatus for applying a bead of sealing material to a sealing surface of a cathode-ray tube and particularly, to a dual position frit applicator for applying frit to sealing surfaces of color-television picture tubes.
In manufacturing some cathode-ray tubes, a bead of sealing material or frit is applied to the sealing surface of a funnel, a faceplate panel is placed on top of the bead, and the assembly is heated to melt the frit and seal the faceplate panel to the funnel. A typical state of the art apparatus for applying frit is disclosed in U.S. Pat. No. 3,701,674 issued to L. B. Kimbrough on Oct. 31, 1972. Although Kimbrough apparatus performs its frit application function well, it is desirable to increase its production rate as measured in tube funnels processed per hour and to apply frit to different size funnels interchangeably. Perhaps the greatest limiting factor to increased production rate with the prior art Kimbrough apparatus is that the apparatus must remain inoperative during loading and unloading of the cathode-ray tube funnels. Furthermore, various parts of the apparatus must be changed in order to handle different size funnels. Therefore, there is a need for a frit applicating apparatus which will overcome these limiting factors and thus yield an increased production rate.